Muffler



M. KATCHER Oct. 3, 1944.

MUFFLER Filed May 20, 1943 2 Sheets-Sheet 1 NVENTOR. Morn KalcherATTORNEY Oct. 3, 1944. M. KAT CHER 2,359,365

MUFFLER Filed May 20, 1945 2 Sheets-Sheet 2 ail- S M I VENTOR. BY armsIadcher ATTOR N EY Patented Oct. 3, 1944 UNITED STATES PATENT OFFICE 11Claims.

This invention relates to mufflers or silencers for use in connectionwith the elimination of the noise caused by the sudden flow of gases,for example, from the exhaust manifold of an internal combustion engine.

It is an object of this invention to produce a mufiler with a resonancedevice inside the main chamber, which device takes part of the gasentering the muiiler and then sends this part back again to flow throughthe bafile with the rest of the gas. In some fprms the resonance devicehas a fixed period as determined by its length, in other forms thelength is continuously adjustable and in still another form the lengthcan be varied in definite amounts. The resonance device acts to reducethe effect of the periodicity of the impulses received from the gasesemitted as a result of the successive explosions in the enginescylinders.

Another object of the invention is the method of production of thespiral member. This memher is a troublesome and expensive one to makeordinarily but with my method it can be economically produced. Itrequires nothing more than a plurality of split washers which are joinedend to end at the split after first having been bent longitudinally toseparate the edges at the split. The method lends itself particularly tothe production of a spiral in which the distance between the successiveturns is varied as this is simply accomplished by separating the splitedges mor and less for the successive washers. In the preferred form thedistance between successive turns increases toward the outlet end of themuffler, in which case the split edges of successive washers aresuccessively increased in ofiset.

Other objects and advantages will become apparent upon further study ofthe description and drawings, in which:

Fig. 1 is a sectional plan of the mufiler with a fixed length resonancechamber, the spiral member being shown in elevation.

Fig. 2 is an elevation of a portion of a spiral member formed of joinedsplit Washers.

Fig. 3 is a section taken along the line 33 of Fig. 2.

Fig. 4 is a section taken along the line 44 of Fig. 1.

Fig. 5 is a sectional plan of a muffler with a continuously adjustableresonance chamber, the spiral being shown only where cut.

Fig. 6 is a partial sectional plan of a mufller with a resonance chamberadjustable to predetermined lengths, the spiral being shown only wherecut.

Fig. 7 is a section of Fig. 5 taken along the line 1l, and

Fig. 8 is a partial sectional plan of a mufiler wherein the housing isgrooved to receive the outer periphery of the spiral member.

The muffler of Figs. 1 and 4 is provided with a casing or housing 9formed of two halves crimped together at flanges l0. Extending centrallythrough housing 9 and end pieces II and I 2 is a resonance tube I3. Endpieces H and [2 are spot welded at their inner edges to tube I 4 and attheir outer edges to casing 9. Supported between tube I 3 and housing 9is a spiral member [4. Member I4 is welded in several places at eachturn to tube l 3. The pitch of the spiral is reversed at points [5 andI6 and increases toward end piece I2. Increasing the pitch of the spiralallows the gas to expand more rapidly thereby reducing its velocity. Ina broad sense it can be said that the spiral has a variable pitch whichdoes not necessarily increase toward the outlet, although this is thepreferred form. For example, the increase could be toward the inlet endof the chamber.

Tube [3 is provided with openings ll near the inlet end of chamber l9and with openings 18 near the outlet end of said chamber. Inside of tube13 is a diaphragm 20. 1

In operation, gas from the successive explo sions of the engine isforced into tube l3 at the inlet end. Part of the gas leaves the tubethrough openings l1 and continues through spiral member 14 entering tube13 again at openings [8 and finally being discharged from the open endof the tube. The other part of the gas received at the inlet end of tubel3 continues along the tube until it strikes diaphragm 20. It isreflected back therefrom and then leaves the tube at openings I! fromwhence it goes along with the rest of the gas about spiral member [4.The second part of the gas is thus out of phase with the first part ofthe gas tending to break up any resonance that might develop in themufller due to the periodicity of the successive quantities of gasreceived at the successive explosions in the cylinders of the engine. Itis well known in the wave theory of propagation that out or phase wavestend to neutralize each other. In making the muflier, the length in theresonance tube I3 between its inlet and diaphragm 20 is determined forthe particular engine type with which it is to be used. As will be seenlater on, this invention includes types of resonance tubes in which saiddistance is not fixed as with the form described above, but isadjustable.

In one method of manufacturing the spiral member, a series of splitwashers are used. In Figs. 3 and 4, for example, each turn 2! of thespiral member is a split washer, the part of a turn extended over by awasher being substantially 360 degrees less the amount of overlap 22.Each washer is bent longitudinally or axially, so that the edges at thesplit are separated longitudinally or axially. One edge at the split ofthe previous washer is then set to overlap the opposite edge of the nextsucceeding washer as shown at 22. The overlapped edges are then weldedby spot welding or otherwise fastened together. In this manner, thecomplete spiral member is formed. To increase the space between turns asthe outlet end of the mufller is approached, the split edges of thewashers are pulled more widely apart. This is an economical method ofproducing the spiral, and further the overlapped edges increase thefriction of the flow of the gas through the mufller.

The mufiler of Fig. 5 is similar to that of Fig. 1 except that thelength of the gas column in the resonance tube 23 can be continuouslyvaried. As before the housing or casing 9 contains a spiral member [4wrapped around a central cylindrical member to which it is welded, inthis case said member being resonance tube 23. The outer edge of spiralmember l4 contacts the inside of housing 9. Openings I! are provided intube 23 near the inlet end of chamber 19 and other openings 68 near theoutlet end of said chamber. Tube 23 extends through end piece H at theinlet end and through end piece 12 at the outlet end. Near the outletend of said tube is fastened by spot welding a spider 24 extendingtransversely across the tube. Spider 24 provides a bearing 25 for screwrod 26. Collars 33 fixed to rod 26 prevent axial movement thereof.Threadedly mounted on screw rod 26 is a diaphragm or obstruction 2'!which is slidably mounted in tube 23. Obstruction 2? prevents the flowof gas by it in tube 23. The lower end of screw rod 25 is provided witha head 28 which is outside of the muffler. In the use of the muiiler of5, resonance with the impulses received from the engine can be avoidedby adjusting the location of obstruction 27 in tube 23. This changes thenatural period of vibration of the gas in the mufiier. Obstruction 21can be set in a continuously varied position in tube 23. In this respectthe muflier of Fig. 5 is different from the mufller of Fig. 6. In thelatter mufiier, obstruction 29 can be set only at predeterminedlocations in tube 30. For most conditions this is a sufficientlyflexible adjustment to overcome resonance. Tube 3!) i provided with setsof screw holes 3| in spaced positions along its length. Obstruction 29has threaded holes which can be set in register with screw holes 3|, andwhen so set, screws 32 can be inserted to hold the obstruction in placein tube 3%. The clot and dash lines show how obstruction 29 could be setin another position. Gas escapes through unocculpied screw holes 3iincreasing turbulence thereby in spiral member M.

The :casing 35 of Fig. 8 is formed with a spiral groove 34 into whichthe outer edge of spiral member i l fits. This gives said memberespecial rigidity.

I claim:

1. A mL tller for an internal combustion engine, including a casingenclosing an elongated chamber, a resonance tube extendinglongitudinally through said chambenbafliemeans alongside said tubeextending longitudinally in said chamber, said casing having an openingtherein at one end of the chamber fOr receiving the gas from the engine,said tube having an opening therein inside of the casing near thereceiving end of the chamber, said casing having an opening therein atthe opposite end of the chamber for the discharge of the gas passedthrough the bafiie means, said tube being closed off against the passageof gas therethrough at a location a substantial distance toward thedischarge end of the chamber from the opening at the receiving end ofthe tube, gas received at the opening in the casing at the receiving endof the chamber passing in part directly through the baflle means to thedischarge opening and in part through the tube to said closed location,being reflected back therefrom and out said tube orpening into thebaiile member.

2. A muiiler for an internal combustion engine including a casingenclosing an elongated chamber, a resonance tube extendinglongitudinally through said chamber, spiral means about said tubeextending longitudinally in the chamher, said chamber and tube receivingat one end the gas from the exhaust of the engine, the tube having anobstruction against the passage of gas therethrough at a substantialdistance from its receiving end, part of the gas received from saidexhaust passing directly through the spiral means to the outlet end ofthe casing, another part of the gas after entering the tube traveling asubstantial distance through it to the obstruction from whence it issent back again out of the tube to pass through the spiral means to theoutlet end of the casing.

3. A mufiler for an internal combustion engine including a casingenclosing a chamber, a resonance tube in said chamber, bafile meansbetween the tube and the casing, said chamber and tube receiving at oneend the gas from the exhaust of the engine, said tube being closed offat a substantial distance from its receiving end, part of the gasreceived from the exhaust passing directly through the baflie means tothe outlet end of the casing, another part of the gas after entering thetube rebounding from where it is closed to pass out the receiving end ofthe tube and through the baiile means to the outlet end of the casing.

4. A muffler for an internal combustion engine including a casingenclosing a chamber, a resonance tube in said chamber, bafile means inthe chamber, said chamber and tube receiving at one end the gas from theexhaust of the engine, means for closing off the tube, and means forsetting the closing off means at diiferent positions along the length ofthe tube, part of the gas received from the exhaust passing directlythrough the baflie means to the outlet end of the casing, another partof the gas after entering the tube being sent back again out of the tubeto pass. through the baiiie means to the outlet end of the casing.

5. A muflier for an internal combustion engine, including a casingenclosing an elongated chamber, a resonance tube extendinglongitudinally through said chamber, baffle means alongside said tubeextending longitudinally in said chamber, said tube extending throughthe casing with an opening for receiving the gas from the engine at oneend of the chamber, said tube having an opening in its side inside ofthe casing near the receiving end of the chamber, said casing having anopening therein at the opposite end of the chamber for the discharge ofthe gas passed through the bafiie means, said tube being closed ofiagainst the passage of gas therethrough at a location a substantialdistance toward the discharge end of the chamber from its side opening,gas, received by the tube from the engine, passing in part out said sideopening directly through the baflle means to said discharge opening andin part continuing through the tube to said closed location, beingreflected back therefrom and out the side opening in the tube into thebaffle means.

6. A muflier for an internal combustion engine including a casingenclosing an elongated chamber, a resonance tube extendinglongitudinally through said chamber, baffle means alongside said tubeextending longitudinally in said chamber, said tube extending throughthe casing with an opening for receiving the gas from the engine at oneend of the chamber, and extending through the casing at the opposite endof the chamber for the discharge of the gas outside of the casing, saidtube having an opening in its side inside the casing near the receivingend of the chamber and another opening in its side near the dischargeend of the chamber, said tube being closed oif against the passage ofgas therethrough at a location a substantial distance away from theopening which is near the receiving end of the chamber, gas, received bythe tube from the engine, passing in part out the side opening of thetube near said receiving end directly through the baffle means, theninto the side opening of the tube near said discharge end and out of thetube to the outside of the casing,

another part of the gas continuing through the tube to said closedlocation, being reflected back therefrom and out the side opening of thetube near the receiving end into the baffle means.

7. A muflier for an internal combustion engine including a casingenclosing a chamber, a resonance tube in said chamber, baflie meansextending through the chamber, said chamber and tube receiving at oneend the gas from the exhaust of the engine, means movably mounted in thetube for closing off the tube, and means for setting the closing 011means at different positions along the length of the tube, said settingmeans extending through the casing to the outside thereof for manualadjustment on the outside, part of the gas received from the exhaustpassing directly through the baffle means to the outlet end of thecasing, another part of the gas after entering the tube being sent backagain by reflection from said closing off means and out of the tube topass through the baflle means to the outlet end of the casing.

8. A muflier for an internal combustion engine including a casingenclosing a chamber, a resonance tube in said chamber, baflie meansextending through the chamber, said chamber and tube receiving at oneend the gas from the exhaust of the engine, the tube extending throughthe casing at the opposite end of the schamber, the gas being dischargedfrom said opposite end of the chamber, means movably mounted in the tubefor closing off the tube, and means for setting the closing off means atdifferent positions along the length of the tube, said setting meansextending through the tube and out its end at said opposite end of thechamber for manual adjustment on the outside of the chamber, part of thegas received from the exhaust passing directly through the baflie means,and out of the chamber at its discharge end, another part of the gasgoing through the tube until reflected back by the closing oiT means topass out of the tube to join the gas passing through the baffle means.

9. A mufiler for an internal combustion engine including a casingenclosing a chamber, a resonance tube in said chamber, bafiie meansextending through the chamber, said chamber and tube receiving at oneend the gas from the exhaust of the engine, the tube extending throughthe casing at the opposite end of the chamber for the discharge of thegas outside of the casing, said tube having an opening in its sideinside of the casing near the discharge end of the chamber, meansmovably mounted in the tube for closing oif the tube, and means forsetting the closing ofi means at different positions along the length ofthe tube, said setting means extending through the tube and out of itsdischarge end for manual adjustment on the outside of the casing, partof the gas received from the exhaust passing directly through the bafiiemeans, then into the side opening of the tube near said discharge endand out of the tube to the outside of the casing, another part of thegas going through the tube until reflected back by the closing off meansto pass out of the tube to join the gas passing through the bafliemeans.

10. A muffler for an internal combustion engine including a casingenclosing a chamber, a resonance tube in said chamber, baflle means inthe chamber, said chamber and tube receiving at one end the gas from theexhaust of the engine, means for closing ofl the tube having aninternally threaded portion, and a screw rod extending along the tubeupon which said portion is threaded, the rotation of the rod varying theposition of the closing oif means along the inside of the tube, part ofthe gas received from the engine passing directly through the bafliemeansto the outlet end of the casing, another part of the gas afterentering the tube being reflected back by the closing oft means to passout of the tube to join the gas passing through the bafiie means.

11. A mufiler for an internal combustion engine including a casingenclosing a chamber, a resonance tube in said chamber, baffle means inthe chamber, said chamber and tube receiving at one end the gas from.the exhaust of the engine, means for closing off the tube movabletherein, said tube having provision at a plurality of spaced fixedlocations for holding the closing off means in position in the tube,part of the gas received from the engine passing directly through thebafile means to the outlet end of the casing, another part of the gasafter entering the tube being reflected back from the closing off meansto pass out of the tube to join the gas passing through the bafiiemeans.

MORRIS KATCHER.

